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What’s the Difference Between Weight Distribution And Sway Control?
These terms often need clarification when discussing towing packages. A weight distribution hitch may have sway control bars that help keep the trailer firmly planted behind a tow vehicle, but a sway control bar doesn’t always help distribute weight.
Weight-Distribution Hitch
A weight distribution hitch is a towing hitch that allows the trailer’s tongue weight to be spread over the axles of the tow vehicle and the trailer. If you have ever seen someone try to tow a heavy load and noticed the tow vehicle’s rear sagging, you know what can happen to a car, truck, or SUV's rear end when the load is too great. Not only do these kinds of heavy loads overload the rear ends, but they also put more pressure on the rear tires, make it harder to stop in emergencies and reduce the ability to steer or control the trailer. In short, this is NOT the way anyone should tow anything.
A weight distribution hitch uses spring arms designed to provide more level towing. These spring arms support the trailer’s weight and distribute weight more evenly. The truck can pull with all four tires on the ground, as the entire load is now evenly distributed over the front axle. This configuration provides better tire pressure, increased steering control, and reduces the wear on the rear end of the towing vehicle. The truck is now pulling the load, rather than the trailer’s weight dictating to the tow vehicle where it should be going.
The two steel arms connect from a modified hitch ball to the trailer tongue via brackets or chains. The spring bars help provide an upward force to counter the weight of the trailer tongue. When the towing vehicle turns, the connections help keep the central area of the tow hitch centered, so there is not as much fluidity with the trailer’s movement.
A weight-distributing hitch like this unit from Camco EAZ Lift on Amazon has built-in sway control that helps keep the trailer centered behind the tow vehicle. This scenario is essential when towing something on a highway or along the Interstate, where wind from oncoming traffic or open areas can push against the side of a camper or large boat. The weight-distributing hitch doesn’t prevent the wind from blowing, but it does provide more support to resist those forces when they happen.
Sway Bars
A sway control bar is a thick stabilizing beam that you attach from your trailer’s ball hitch to the tongue of the trailer. The primary purpose is to create an additional connection point to prevent a bumper pull trailer from moving back and forth while towing. Most anti-sway bars use friction to resist the pivot of the trailer’s coupler on the hitch ball. The friction bars gain steering control when the bump-pull trailer moves sideways.
(Consider the connection between your trailer’s coupler and hitch ball as one big pivot point. To tow, the trailer ball and coupler are locked together, and this is great for pulling in a straight line with no other force than the tow vehicle affecting the trailer. The coupler and ball need to pivot to go around curves. That pivot point makes the trailer to be susceptible to other forces.)
An unevenly loaded trailer, a gust of wind, or a semi-truck can create a sideways draft as it passes and push a trailer sideways. If the lateral forces are too great, the trailer is pushed in a direction that the tow vehicle never intended, and if it is severe enough, it can create a rollover of both the trailer and the tow vehicle).
A sway bar like the one from Curt Mfg on Amazon simply makes it harder for the outside forces affecting a trailer as you tow to get the upper hand. While installing a sway bar can help reduce some trailer sway (roll-over), it will not prevent trailer sway from happening. The primary purpose of a sway bar is not to help with weight distribution but to counter trailer sway.
When Do I Need A Sway Bar?
According to etrailer.com, RV owners pulling trailers under 24’ and weighing less than 5 - 6,000 lbs can use only one stabilizer bar. However, it should be noted that while friction bar sway control systems may be great for small trailers, flatbeds, or simple campers, anything larger or heavier needs two sway bars.
There are some disadvantages to using a friction sway bar. Namely, these kinds of bars are generally incompatible with surge brakes that most campers have and must be removed before backing up. (The force is different when backing up on a curve, so this reverse maneuver will likely ruin the bar entirely).
In addition, the sway bar is a reactive system, meaning that it counters trailer sway after it happens, not before. (In its defense, it does stiffen the connection, but it applies friction to slow trailer sway when it detects it, not before).
When is a Weight Distribution System Needed?
You need to use a weight distribution system when you notice that the weight of the trailer’s tongue seems too much for the hitch ball. If you connect the trailer and it sags the rear end of the tow vehicle, you should consider adding a WD system. Because this type of hitch will help balance the trailer and tow vehicle load by spreading the trailer/vehicle weight to the front axle.
The advantage of a weight distribution system is that the system is compatible with surge brakes and does not have to be disconnected when backing up. WD systems are perfect for towing larger medium-sized trailers or campers that range from 24’ - 30’. Most weight distribution hitches have built-in sway control to offer more steering control over towing situations.
Which System is Better - Weight Distribution or Sway Bar
Sway bars are fine tools for light to moderate towing if you do not plan to tow for a long distance. If you are going to do any backing up (other than straight-line backing), then a sway bar is not feasible. Weight distribution hitches are better for towing larger to medium size trailers, boats with heavy-weight ratings, or units susceptible to trailer sway. Most WD systems provide both weight distribution and sway control.
Will A WD hitch Let Me Tow More Weight?
A weight-distributing hitch will only let you tow more than the max tongue weight or gross vehicle weight your towing vehicle is built for. (If you need to exceed your towing capacity, get a bigger hitch or a different truck). A WD system will let you tow up to maximum operating weight, but no system will allow you to exceed the weight limits both the tow vehicle and your trailer were designed to handle.
Do Weight Distribution Hitches Cost More?
Weight distribution systems are more expensive than sway control bars since more components are involved. A WD system will cost more depending on the features and manufacturer. One of the best systems is the Equal-i-zer hitch, which offers a 4-point sway control system and is one of the most popular WD distribution systems on the market. The average price of a sway bar is usually less than $100. (Considering the cost of a trailer accident, this is a small price to pay for more sway control).
